Title

Regressive and Early Onset Autism Spectrum Disorders: A Comparison of Developmental Trajectories, Autistic Behaviors, and Medical Histories

Date of Completion

January 2010

Keywords

Psychology, Developmental|Psychology, Clinical

Degree

Ph.D.

Abstract

Reports of early regression, or skill loss, in individuals with autism spectrum disorders (ASDs) have been reported since the condition was first described but this has been an area of controversy. This study examines the rates and types of regression in a community-acquired sample of 163 children (mean age=26.3 months) diagnosed with an ASD after a comprehensive evaluation; 96 were seen for a re-evaluation at approximately age 4. The 130 males and 33 females were diagnosed at the initial evaluation with Autistic Disorder (45.4%), PDD-NOS (42.3%), or ASD-low mental age (12.3%), a research category for children who met the criteria for an ASD with a developmental level below 12 months. The overall regression rate was 38.7%; the mean age of language loss was 17.1 months while the mean age of other loss was 15.9 months. Those with Autistic Disorder displayed higher rates of overall regression, as well as losses of specific skills, while the lowest rate was in those classified as ASD-low mental age. Although there was a trend for the composite cognitive score to be lower in the regression group at both evaluations, there were no significant differences in specific cognitive skills or any adaptive skills; however, floor effects may have been a factor. Children who regressed displayed significantly higher mean number of ASD symptoms, especially stereotyped and repetitive behaviors, which were higher at both evaluations. Notably, children with regression presented differently in their first year than those with early onset ASD; they had significantly fewer feeding problems and met all of their developmental milestones at an earlier mean age. In summary, the regression and early onset groups appear to differ from each other in many significant ways, with more typical early development followed by a more impaired later presentation in the regression group. ^